The long-term objective of the planned research is to provide a better understanding of the central consequences of nerve injury in humans. In working toward this objective, this research will study the effects of injury of hand nerves on cortical and subcortical levels of the somatosensory system of monkeys. The specific aims are to: (1) evaluate how central "fringe" projections from intact nerves contribute to topography changes in primary (area 3b) cortex after nerve injury, (2) evaluate the effects of neonatal nerve injury on the development of topographical patterns of representation in primary (area 3b) cortex, and (3) evaluate the effects of nerve injury on subcortical patterns of termination of injured or adjacent intact nerves in the spinal cord and cuneate nucleus. Neurophysiological mapping techniques will be used to study cortical organization and transganglionic transport of horseradish peroxidase from peripheral nerves will be used to study subcortical organization. These results from monkeys will provide a better understanding of (a) possible mechanisms of central reorganization after nerve injury, (b) age-related differences in central recovery after injury, and (c) the reactions of different levels of the brain to peripheral injury. This research is directly relevant for understanding neurological changes after peripheral injury or amputation, and is pertinent for understanding human disabilities associated with central injuries and sensory and communicative disorders in general.